Compilare: main.cpp: In function 'void dfs(int)': main.cpp:31:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[nod].size(); i++){ ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:53:18: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] s[i]=NULL; ^~~~ main.cpp:40:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("lant.in", "r",stdin); ^ main.cpp:41:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("lant.out", "w", stdout); ^ main.cpp:44:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &k); ^